This invention relates to golf clubs, more particularly to golf club shafts. More particularly still, this invention relates to an improved aerodynamic golf club shaft.
Currently, golf club shafts are hollow steel or graphite tubes that are relatively thick at the grip end of the golf club, and narrow as the clubhead is approached. Typically, current golf club shafts have a series of steps therein. The thickness of the shafts change to a narrower thickness at each step.
Golf club shafts must meet the requirements of the United States Golf Association Rules of Golf to be considered xe2x80x9clegalxe2x80x9d for tournament play. The USGA Rules require in Appendix II, Rule 4-lb, that the shaft be xe2x80x9cso designed and manufactured that at any point along its length:
(i) it bends in such a way that the deflection is the same regardless of how the shaft is rotated about its longitudinal axis; and
(ii) it twists the same amount in both directions.
This Rule is believed to be the reason that golf club shafts are currently of circular cross section. Since golf club shafts have previously been believed to require circular cross sections, there has been little opportunity to make golf club shafts more aerodynamic. Another reason golf club shafts are not made more aerodynamic is believed to be an underestimation of the amount of drag created by the shaft when a golf club is swung.
Thus, a need exists for an improved golf club shaft that conforms to the Rules of Golf and is more aerodynamic than current golf club shafts. In particular, a need exists for an improved golf club shaft that allows the golf club to be swung faster by the player with the same or less effort to create more power, and longer shots.
These and other objects of the present invention will be more readily apparent when considered in reference to the following description and when taken in conjunction with the accompanying drawings.
The present invention relates to an improved aerodynamic golf club shaft. The improved aerodynamic golf club shaft comprises a tube that has an exterior with a non-circular cross section.
The golf club shaft may have an elliptical exterior cross section in one preferred embodiment. The golf club shaft of several embodiments of the present invention is based on the following principle. The shaft has a leading edge that is on the half of the shaft aligned with the face of the golf club and a trailing edge on the half of the shaft aligned with the back of the clubhead. At least a portion of the leading edge of the shaft has a smaller radius of curvature than the leading edge of an equivalently sized conventional shaft having a circular cross section.
A non-limiting number of ways are disclosed of providing a golf club shaft with such a cross section, and still retaining the bending and flexing properties needed to conform to USGA specifications. These include: (1) slipping a hollow sheath having an elliptical exterior cross section onto a standard golf club shaft or other shaft having a circular cross section (i.e., retaining the sheath by friction fit); (2) connecting such a sheath at points spaced equally radially around a circular shaft; (3) adhering a material to the leading edge of a circular shaft; or (4) constructing a hollow shaft having an aerodynamically shaped cross section with walls having different wall thicknesses.
This application also discloses improved mechanisms for connecting golf club shafts to club heads, and in particular to mechanisms that allow shorter hosels to be used, especially on iron golf clubs.